class_docstr: A node in an OverlayGraph. Corresponds to a TensorFlow Tensor.
    
code: def as_name(node):
      if isinstance(node, str):
          return node
      elif isinstance(node, (OverlayNode, tf.Tensor)):
          return node.name
      else:
          raise NotImplementedError
  
imports: from collections import defaultdict
  import numpy
  import tensorflow
label_desc: Use image node_id 2 for calling the OverlayNode obj's underlying member method code with example usage: obj.as_name(node) and returns: node, node